This invention relates to an automatic stop device for a tape recorder and more particularly to an automatic tape-recorder stopping device operated by logic control.
An automatic tape-recorder stopping device operated by logic control is provided with an electronic counter which, at the time of recording, carries out addition in synchronization with pulses issued at a frequency proportional to the number of rotations of, for example, a take up reel, and, at the time of rewinding, performs subtraction in synchronization with pulses sent forth at a frequency proportional to the number of rotations of the take up reel. When the contents of the electronic counter are brought to zero, an output pulse signal is produced from the counter. A motor circuit is opened in response to the output pulse signal, automatically stopping the tape recorder. With such type of automatic tape recorder-stopping device, an electronic counter of, for example, the 3-digit type is generally used. Now let it be assumed that recording is started with a number of zero at which the electronic counter is preset; when the counter counts, for example, 185, recording is brought to an end; and the magnetic tape is rewound to a point at which recording was first started. At this time, the counter subtracts the number proportional to a number of backward rotations of the take up reel from the count contents i.e. 185. When subtraction proceeds to zero, the counter generates an output pulse to open the motor circuit, thereby stopping the drive of a motor. At this time, however, the take up reel makes a few excessive rotations due to the inertia of a flywheel. As the result, the contents of the counter are further subtracted to, for example, 998. Where, under this condition, the tape recorder is operated for reproductive, the take up reel makes a normal rotation, carrying out addition as 998.fwdarw.999.fwdarw.000. When addition is carried to a specified number of 000, the motor is generally designed to be brought to rest. To prevent such undesirable stop of the motor when the operation of the tape recorder is made ready for reprodution after completion of rewinding, is may be contemplated to provide a braking device for forcefully braking the flywheel in response to an output signal from the counter at the time of rewinding or provide a seperate switch to control a motor-stopping circuit. When, with the latter method, the switch is depressed, the motor stopping circuit is operated to stop the motor in response to an output signal from the counter. After the stop of the motor, the motor-stopping circuit is reset, preventing the motor-stopping circuit from being set, unless the switch is depressed again. However, the above-mentioned process involves the complicated arrangement of a tape recorder and an electric circuit, obstructs the miniaturization of the tape recorder and unavoidably increases its cost.